Makers of mobile devices distributed a total of 101m smartphones in the last three months of the year, up 87 per cent from the same period a year earlier, according to International Data Corp, the market researcher.

IDC had earlier said that PC shipments reached 92m units in the fourth quarter, up less than 3 per cent.

Analysts had expected smartphones to take the lead at some point in 2011, but the transition happened more quickly as a wide range of manufacturers of mobile devices embraced Android, the malleable open-source operating system from Google.

“Android continues to gain [market share] by leaps and bounds, helping to drive the smartphone market” said Ramon Llamas, IDC analyst. “It has become the cornerstone of multiple vendors’ smartphone strategies, and has quickly become a challenger to market leader Symbian.”

Android passed Apple’s phone software and Nokia-backed Symbian as the most widely adopted program for smartphones at the end of last year, according to research group Canalys. Because Google’s software is used in devices made by other groups, Nokia, which makes smartphones as well as the Symbian software, is still in the lead in terms of smartphone shipments.

The Finnish company’s unit share widened to 28 per cent from 20 per cent in the quarter, IDC said.

Apple’s iPhone, meanwhile, nearly doubled its share from the final quarter of 2009 to 16 per cent in the final quarter of 2010, passing Research in Motion, maker of the BlackBerry, to gain the number two spot.

In revenue and profit terms, Apple does much better per phone, as many Nokia products are less expensive and offer fewer functions.

The market for PCs continues to grow, setting another shipment record in the quarter just ended. But the increases are much smaller than in past years. That is in part due to their higher average price relative to phones and to slower innovation in the segment.

The PC market would be higher if IDC included tablet computers in their figures. Apple alone sold about 15m iPad tablets in 2010 and more than 7m in the fourth quarter, which would have brought the PC category close to level with smartphones.

Many more companies are introducing tablets this year and their sales are expected to more than double as a whole in 2011.

The growth in smartphones will continue to surge, analysts said, as the high-end models improve and the middle tier gets more affordable.

“IDC expects vendors to provide more mid-range and low-end smartphones at lower prices to reach the mass market” this year, said Mr Llamas. “Even high-end devices will become available at lower prices.”